1. Field of the Invention
The present invention relates to a lighting device such as the combination lamp provided with a lens longer in the horizontal directions thereof and attached to the exterior of vehicles.
2. Prior Art
In the case of the rear combination lamp, for example, having a lens longer in the horizontal direction thereof, the tail stop lamp which emits red light, the turn signal lamp which emits orange light, and the backup lamp which emits white light are combined with one another to form the lighting device. The tail stop lamp is a combination of the tail lamp which informs persons behind of the presence of a vehicle at night and the stop lamp which emits light when the vehicle is braked. The turn signal lamp serves to tell the change of that lane on which the vehicle is running and the backup lamp serves to illuminate behind and tell that the vehicle is to move backward.
In the case of this lighting device, however, there arises the problem of false lighting. This is a phenomenon that sun light strikes against the lighting device and its is reflected by the prism on the back of the lens or the reflector in the lighting device in the daytime to show as if the lighting device were lit. This phenomenon is also sometimes caused at night when the lighting device is illuminated by the light of headlamps of other vehicles.
When this false lighting is seen at the tail stop lamp, for example, there is a danger that the vehicle behind puts on an emergency brake, misconceiving that its preceding vehicle has been braked, to thereby make persons ridden together in it feel almost dangerous or cause it to be clashed from behind.
In order to prevent this false lighting, plural light shielding stripes which serve to shield light entering from outside are arranged on the front or back of the conventional lens in the horizontal direction thereof, but they are arranged uniformly on the whole surface of the lens to thereby reduce the light distributing capacity of the lighting device.
Further, a trend has arisen these days that the lighting devices are made thinner. When the lighting devices are made so, they can be made lighter in weight and their material cost can be reduced. In the case of the rear combination lamp, the volume of the trunk room can be made larger. When the lighting devices are made thinner like this, however, they cannot give any profound feeling to persons who see them from their lens side, and they also cannot satisfy those people who have asked these days to have goods of high grade.